Sander



Nov". 15, 1932. s. v. BOWLBY 1,887,620

SANDER Filed Oct. 2. 1930 2 Sheets-Sheet 1 IN! 'EN TOR.

hcrry V. Bowlby BY v4 g A TTORNEY.

Patented Nov. 15, 1932 UNITED STATES PATENT OF-FLCE Application filed October 2,

This invention relates to sanding devices, that. is, to a machine for sanding surfaces. The device is ada ted to be operated b motive fluid, preferably, air. and it is capa le of 1930. Serial No. 485,852.

provided with stops 24, projecting inwardly from their ends and of less diameter than the diameters of the cylinders. The valve cylinders 14 and 15 are connected to piston cylin- 5 holding sheets of sand-paper and move them ders 25 and 26 by conduits or pipes 27 and 28, 55

- 3-3 of Figu at the upper end of whichis a valve seat: 6 pistons.

"overthe surface to be abraided.

Theinvention consists in certain parts and combination of parts, all of which will be specifically described hereinafter, reference beingl-had to the accompanying drawings in whic Fig. 1 is a side elevational view of a device constructed in accordance with my invention, the fluid-admitting chest being shown in section.

Eig. 2 is a top plan view of the device.

Fig. 3 is a cross-sectional view on the line re 1. I

F 4 isa detailed perspective view of one of the sand-paper-holding clamps and Fig. 5 is a diagrammatical view of the piston and valve arrangement.

' Referring now to the drawings by numetals of refe once 1 designates a head formi iig a fluid-admi tting chest. The head is provided withan inlet port 2 connected to a hollow handle 3 supplied with air or other motive fluid through a hose connection. 4. The inlet 2 discharges into the fluid chest 5 adapted to be closed by a valve 7 normally urged on its seat by a spring 8, one end of which bears against the valveand the other against the-bottom of the chest. Projecting through the'-,gland '9 in the top of the chest is a valve stem 10 connected to an operating handle 11 pivoted at 12 to the head. At the bottom of the chest is an outlet port 13 adapted to communicate with two valve-contain ngcylinders l and 15 through a cross port 16 .Two-vilve members 17 and 18 are adapted to reciprocate in the cylinders 14 and 15 as will be clearly seen by reference to Figiire 5. Each valve member is provided wit two end heads'19 and 20, spaced from, collars 21 and 22 to provide spaces between the collars and the respective heads and a space 23 be-" tween the respective collars.

The ends of the cylinders 14 and 15 are 7 connected to the valve cylinder 14 near its center and to the piston 25 at its respective ends. Similar conduits or pipes 29 and 30 connect the valve cylinder 15 with the piston cylinder 26. The ends of cylinder 14 are. 0 connected to the cylinder 25 by conduits or passage-ways 31 and 32. Similar conduits 33 and 34 connect the valve cylinder 15 with the piston cylinder 26. The'cylinder 14 has exhaust ports 35 and 36 near its respective .5 ends and similar exhaust ports 37 and 38 are provided for the cylinder 15. 39 and 40 are ports in the ends of the valve member 17 and Similar ports 41 and 42 are in the ends o the valve member 18. i

In the piston cylinder 25 is'a freely movable piston member having end-heads 43 and 44 and an intermediate head 45 spaced from the end-heads by constricted portions 46 and 47. A similar piston member 48 is in c linder 26.-

The two pistons are connected y a cross link 49 pivoted to the bottom of the head at 50 and having ball and socket connections at its ends with the intermediate heads of the Each piston carries, aplate. These are designated-51 a'nd.52. On the respective ends of the plates are longitudinally disposed downwardly and upwardly curved fingers 53 having their inner ends pivoted to the plates 3:, at 54. The fingers on one plate are connected to the fingers on the opposite plate by the coil springs55. Each plate has downwardly projecting edge flanges 56 and 57 in the angles of wh ch are clamping bars'58 a d 59, having 00 upstanding fingers 60 and 61 w ich project through openings in the plate having their upper ends connected'by coil springs 62 so that the fingers are rocked inwardly by the I action of the springs to ur the clamping 05 bars or rods against the anges to clamp sand-paper 63 between them. The fingers canv be urged outwardly by a'double cam 64 pivoted at 65 toeach plate and each cam has a handle 66 by means of which the cam can be 1 bars cooperating with the, flanges, fingers on the clamping bars, springs connecting the fingers to force the bars toward the flanges and acam for spreading the fingers to move the si ature. Wi ma bars away from the flanges.

whereof I afiix m In testimony SHERRY V. .B

bowing too much as the sander passes over the surfaceto be treated.

It will be noted that the stops 24 limit the longitudinal movements of the valve memthe crossbar,it will move in opposite directions to-shift the sand- 4 "lyused.

bers so that the inports 27 {28, 33 and 34 will not be closed oil by the ends of the valve members.

When the parts are assembled, motive fluid suchas air can be admitted tlirou the head 1 (by unseating the valve 7) into th of the valve cylinders and from the valve cylinders to file pistoncylinders, for example, through ports 28 and 29-(see Figure 5), while air or other motive fluid is exhausting out of the opposite ends of the cylinders, for example,

through ports 27 and 30 and out through the outlet ports 35 and 38. When the pistons reach the ends of their strokes in one direction, the ports 31 and 34 will open to the valve cylinders to shift the valves to the positionsshown in Figure 5-so that air now enters the opposite ends of the piston cylinders to reverse the pistons ,and this alternate action continues as long as motive fluid is supplied.

Inasmuch as the are connected by obvious'that they must paper-carrying plates and sets of fingers in opposite directions. Therefore, there will be a constaht reciprocation of the sand-paper applicators (consistin of the fingers and their appurtenances) an it will be obvious that the fingers are-yielding enough so that. some of them may move overv irregular surfaces while others remain on the flat surface.

I maynot employ the 67 under all conditions blit wherea straight flat surface is to be sanded, I find the pads tobe advantageous- Iclaim and desire to secure by Let- What ters Patent is 1. A sanding machine com rising a head, a pair of power istons carri by t e head,- a

pivoted crossr connecting- 'the. pistons,

sand paper holders actuated by the pistons to reciprocate in alternate directions, said sand-paper holderscomprising plates having pivoted fingers at their respective ends and flexible connections between the ends of the fingers in spaced relationto the plates.

'2. A sanding-machine com a head,

a pair'of power pistons bythe head, a piv crpssconnecting the pistons,

sand-paper holders actuatedby the pistons to reciprocate inalternate directions and ndaper clamps carried by the holders consist ng of plates having flanges, clamping 

